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Wednesday, April 26, 2017

Highlights: Continental Carbonate Conditions

Continental
carbonates are distinct from their marine cousins, but like them, contain
numerous proxies for the environment in which they formed. Yet, continental
carbonates can be of two general types: those formed ambient temperature from
calcium bicarbonate–enriched waters and those associated with hyperalkaline
thermal springs, from fluids commonly depleted in dissolved inorganic carbon. Both
are favored under distinct conditions, yet how closely they each reflect their
environment is unclear. To better understand these complexities, Leleu and others examined
travertine forming at DIC-depleted hyper-alkaline springs with pH up to 12.
Their multi-disciplinary approach ranged from macroscopic to microscopic scale,
analyzing travertine samples to assess the relationship between the petrologic
features and fabrics and the geochemical and isotopic signatures. The results
illustrate the potential of these deposits as proxies of past climatic record
and atmospheric CO2 sequestration.